"Ground" in this case refers to a protective "earth ground". It is for the protection of humans.

Normally, the earth ground carries no current at all, nor should it be used for that purpose; it is simply there in case there is a short from the mains power to the case of the equipment. A short from mains power to ground will result in the circuit breaker or fuse opening up, instead of having mains power connected to the equipment case - which would be a dangerous situation.